The present invention relates to a cleaning system as can be applied in a combine harvester. A combine harvester is an agricultural tool to harvest grain crops. In general, the crop is harvested by a reaping operation, followed by a threshing operation, and a subsequent separation operation in which the straw is separated from a grain and MOG (material other than grain) mixture. In order to separate the grain from the MOG, a combine harvester is equipped with a so-called cleaning system (also known as a cleaning shoe) which may typically include one or more sieves. During a transport of the harvested crop along the sieve, a separation of grain and MOG may take place by means of apertures provided in the sieve. Typically, a sieve as applied in a cleaning system comprises a plurality of spaced apart louvers, a spacing between the louvers providing the apertures.
In order to increase the cleaning capacity of the cleaning system, air blowing systems have been added to provide in an upward air flow through the apertures of the sieve.
The present invention aims to provide a further improvement of the operation of a cleaning system in that it increases cleaning capacity.